1. Field of the Invention
The present invention relates to a recording apparatus capable of being driven by a rechargeable battery.
2. Description of the Related Art
In recording apparatuses, such as printers, facsimile apparatuses and the like, an image comprising a dot pattern is recorded on a recording sheet, such as paper, a plastic film or the like, by driving an energy generating member of a recording head based on image information.
The recording apparatuses are classified into ink-jet apparatuses, wire-dot apparatuses, thermal apparatuses and the like according to their respective recording methods. In ink-jet recording apparatuses, recording is performed by discharging droplets of a recording liquid (ink) from discharging ports of a recording head and causing the discharged droplets to adhere to a recording material, such as paper or the like.
So-called bubble-jet-type ink-jet recording heads which utilize heat energy for discharging ink droplets have the advantage that a small-size head can be easily obtained because discharging ports can be arranged at a high density. Hence, heads of this type are most suitable for portable small-sized recording apparatuses.
Although recording apparatuses ordinarily use an AC power supply as their main power supply, portable small-sized recording apparatuses use, in some cases, two power supplies, i.e., an AC adapter and a rechargeable battery.
When powering a recording apparatus with a battery, since the output voltage of the battery decreases as the remaining capacity of the battery decreases, it can become difficult to drive respective units of the apparatus. For example, if the apparatus suddenly stops during a recording operation, received recording information may be lost. In the case of an ink-jet recording apparatus, ink discharging ports of the recording head may not be closed by a capping member.
Accordingly, when powering a recording apparatus with a battery, particularly an ink-jet recording apparatus, it is necessary to provide means for charging a rechargeable battery when the capacity of the battery decreases to a value less than a predetermined value.
In conventional recording apparatuses having a rechargeable battery and a battery charging function, the operational mode of the apparatus is manually switched between a printing mode, i.e., an ordinary recording mode, and a battery charging mode.
However, configurations requiring manual switching between the printing mode and the charging mode require a troublesome manual operation, resulting in an inefficient use of the apparatus.
If recording processing and charging processing are performed in parallel, the apparatus can be efficiently used because it is unnecessary to perform a manual switching operation. However, this approach requires a large-capacity battery which allows parallel execution of recording processing and charging processing, resulting in an increase in the size and the cost of the recording apparatus.
Further, in this type of recording apparatus, the voltage and the charging current of the battery are typically detected during charging by performing analog-to-digital conversion by detecting, for example, a fully charged state or the like. However, when driving a motor and a print head during recording processing, the ground level of a signal fluctuates due to the relatively high driving current required by these components. If an analog-to-digital conversion circuit is operated in this state, the resulting accuracy of conversion decreases, which can cause unstable charging control.
In order to solve such problems, an approach may be considered in which current consumption in the apparatus is detected and charging is automatically performed only while the value of the detected current consumption is less than a predetermined value. However, for that purpose, it is necessary to provide means for very precisely detecting current consumption in the apparatus, resulting in an increase in the size and the cost of the apparatus. Furthermore, due to a voltage drop caused by a current-sensing resistor, the battery voltage will drop below a minimum useful value at an earlier stage, resulting in a shortened battery operating time period per charging operation.
It is an object of the present invention to provide a recording apparatus having a function of charging a battery with an improved operability without increasing the size and the cost of the apparatus, and a method for charging the battery.
It is another object of the present invention to provide a recording apparatus having a battery charging function in which the operational mode of the apparatus can be automatically switched between a printing mode and a charging mode.
One aspect of the present invention relates to a recording apparatus for performing recording by driving a recording head using electric power supplied from an external power supply or a battery. The recording apparatus includes a charging circuit for charging the battery using the electric power supplied from the external power supply, and control means for controlling the charging circuit based on retraction information indicating whether or not the recording head is at a retracted position where recording is not performed.
Another aspect of the present invention relates to a method for charging a recording apparatus which performs recording by driving a recording head using electric power supplied from an external power supply or a battery, and which includes a charging circuit for charging the battery using the electric power supplied from the external power supply. The method includes a control step of controlling the charging circuit based on a result of detecting whether or not the recording head is at a retracted position.
Another aspect of the present invention relates to a recording apparatus that includes a recording head, a power supply circuit, and a control circuit. The power supply circuit is capable of supplying power to the recording apparatus when external power is provided to the power supply, and is also capable of supplying power to the recording apparatus when power is provided to the power supply from a battery. The charging circuit charges the battery from the external power only when the recording head is capped, and inhibits charging of the battery when the recording head is uncapped.
According to configurations of the present invention described herein, it is possible to interrupt charging while a motor and the recording head are driven, and thereby improve the operability of the apparatus.
The foregoing and other objects, advantages and features of the present invention will become more apparent from the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings.